We propose to continue and expand our investigations of computer-summated cerebral potentials elicited in human subjects by discrete electrical stimuli delivered to the pulp of individual teeth via electrodes implanted into dentine. This research will include: a study of the relationships among intensities of electrical stimulus of tooth pulp, amplitudes of cerebral evoked potentials and subjective estimates of elicited pain; a comparison of cerebral potentials evoked by electrical stimulation of tooth pulp, labial skin and median nerve; a study of the effects of anesthetic block of the inferior alveolar nerve on cerebral potentials evoked by electrical stimulations of tooth pulp and labial skin and of their relationships to the alteration, loss and recovery of dental and cutaneous sensibilities; an investigation of the cerebral potentials related to the omission of painful electrical stimuli to tooth pulp; and, an attempt to demonstrate cerebral potentials associated with the perception of a particular type of clinical dental pain and to compare them with the potentials elicited experimentally by painful electrical stimulation of tooth pulp.